This invention relates to rock crushers and more specifically to the crushing blocks in impact crushers having vertical shaft impellers.
The need for crushing rock on a large scale probably dates back to the time of the Persians who had a formidable empire during the 500 years proceeding the Christian era and needed roads to transport their amines from Asia Minor to India. Later, the Romans built over 50,000 miles of roads at the height of their imperial power.
It is doubtful whether either the Persians or Romans used any type of rock crushing machines even though rocks of fairly small uniform size were a major element in the design.
The earliest machines used to crush rock were probably tilt-hammers which were driven by water and later by steam engines. Tilt-hammers were in use at least as early as the mid-seventeen hundreds but steam engines to drive these tilt-hammers did not come into use until the mid-eighteen hundreds.
The earliest use of a rotating wheel spinning on a vertical axis to propel rock against a hard surface is unknown. Potter's wheels with vertical shafts have been found which date back to about 3,500 B.C. but Applicant's first knowledge of vertical shaft rock impellers is the Hadsel centrifugal rock crusher, U.S. Pat. No. 1,857,539 granted in 1932.
A primary problem in all impact crushers is the severe abrasion to the impact portions of the crusher. This abrasion is so rapid that some crushers can only be operated a few hours before adjustments or even replacement of the blocks must be made. These adjustments and replacements must be made quickly, easily and inexpensively or the crusher will be too costly to operate.
Hadsel discloses breaker blocks which were hung on hooks around the periphery of the wheel but the blocks did not have any radial adjustment to vary the distance the rock was thrown before striking the breaker blocks. Rotational adjustment to present a different portion of the face of the block to obtain evenness of wear was possible but the adjustment could not be made from outside the machine.
Morrissey, U.S. Pat. No. 2,357,843 disclosed a sectional breaker ring which could not be adjusted radially, vertically or rotationally.
Dodds, U.S. Pat. No. 2,867,387 discloses a plurality of impact targets formed of ceramic material in cylindrical collars. No radial or vertical adjustment was provided.
Conley, U.S. Pat. No. 2,981,490 discloses target impacters similar to Dodds and also fails to disclose any radial or vertical adjustment.
Sellars, U.S. Pat. No. 2,991,949 utilized flat breaker surfaces mounted on a circular sectional liner but disclosed no radial, vertical or rotational adjustment of the flat breaker surfaces.
Wirth, U.S. Pat. No. 2,992,783 discloses a bowl liner formed in sections to serve as crushing blocks. No radial, vertical or rotational adjustment is shown.
Behnke, U.S. Pat. No. 2,992,784 attempted to solve the wear problem of crushing blocks by providing shelves to retain crushed material so that the rocks were hurled against the crushed material. This system results in a great loss of energy since the crushed material in the shelves only seves to cushion the impact of the rocks to be crushed.
Bridgewater, U.S. Pat. No. 3,044,720 discloses a plurality of arcuate segmented breaker blocks pivotally mounted around the circumference of the impeller wheel. Each of the three arcuate segments may be pivoted by an adjustment bolt. While some radial adjustment is possible, there is no vertical or rotational adjustment.
Adams, U.S. Pat. No. 3,058,679 discloses a plurality of breaker plates but no radial, vertical or rotational adjustment from the breaker plates as wear progresses.
Bridgewater, U.S. Pat. No. 3,074,657 discloses a breaker plate structure with removable inserts but does not provide any radial or vertical adjustment. Rotational adjustment would be possible but relatively unimportant since the inserts appear to be very narrow.
Bridgewater, U.S. Pat. No. 3,088,685 discloses a plurality of removable breaker plates but there is no vertical or radial adjustment possible. The breaker inserts could be rotated 180.degree. and reinserted but could not be rotated 90.degree..
Bridgewater, U.S. Pat. No. 3,093,329 discloses a plurality of serrated breaker plates which can not be adjusted radially or vertically. A 180.degree. rotation of the breaker plates is possible but not a 90.degree. rotation.
Bridgewater, U.S. Pat. No. 3,110,449 discloses breaker shoes with removable inserts but no radial or vertical adjustment. Some inserts may be rotated 180.degree. but not 90.degree..
The Behnke crusher apparatus U.S. Pat. No. 3,148,840 discloses crusher blocks which can be rotated in 90.degree. increments but can not be adjusted radially or vertically.
Adams, U.S. Pat. No. 3,150,838 uses breaker plates which can not be adjusted radially, vertically or rotationally.
Rhodes, U.S. Pat. No. 3,155,326 uses breaker plates which can not be adjusted radially, vertically or rotationally.
Herman, U.S. Pat. No. 3,168,991 discloses removable breaker segments which can not be adjusted radially, vertically or rotationally.
Miller, U.S. Pat. No. 3,174,698 discloses a plurality of breaker bars held in sockets but there is no radial, or vertical adjustment. It is possible to rotate the bars 90.degree. and to invert the bars. None of these adjustments can be made from the outside of the rotary rock crusher.
Vifian, U.S. Pat. No. 3,204,882 discloses segmented breaker members which can not be adjusted vertically, radially or rotationally.
Behnke, U.S. Pat. No. 3,334,823 discloses a plurality of breaker blocks which can not be adjusted radially or vertically. The lid of the device must be removed in order to replace the breaker blocks.
Behnke, U.S. Pat. No. 3,300,152 discloses a plurality of breaker blocks pivotally mounted so that the angle at which the breaker intercepts the rocks to be broken can be adjusted. There is no radial, vertical or rotational adjustment possible.
Wood, U.S. Pat. No. 3,474,974 discloses breaker blocks made of at least (3) segments which are interchangeable so that if the central block receives more wear it can be interchanged with the upper or lower segment. No radial adjustment is possible although the segments can be rotated 180.degree.. No adjustment is possible from the outside of the crusher.
Parker, U.S. Pat. No. 3,540,667 also shows segmented breaker blocks which can be interchanged or even rotated 180.degree. but no radial or vertical adjustment is possible. All adjustments are made within the machine.
Johnson, in U.S. Pat. Nos. 3,873,047, 4,065,063 and Re. 29,798 recognized the uneven wear on the impact blocks and therefore provides for the reciprocating vertical movement of the entire assembly of breaking blocks on a timed sequence. Thus, rocks thrown from the impeller strike different parts of the breaker blocks along their vertical axis.
Ackers, U.S. Pat. No. 4,090,673 provides breaker blocks which have no radial or vertical adjustment but they can be rotated 180.degree. to even the wear. Replacement is effected from inside the crusher.
Burk, U.S. Pat. No. 4,126,280 provided radial adjustment and rotation of the anvils 180 degrees only. No vertical adjustment was possible and all adjustments had to be made from inside the crushers. No adjustment of any kind could be made during operation of the crusher.
There are two schools of thought on whether rock is flung from the high speed rotating disk radially or tangentially. Ackers, exemplifies the tangential school and orients his breaker blocks so that the flat surface is at right angles to the tangent line from the periphery of the rotating impeller. On the other hand, Morrissey, supra provides a breaker ring which provides a surface at right angles to the radius from the center of the impeller. Since no one has yet looked inside an operating crusher to determine whether the trajectory of the rocks is tangential or radial, the debate continues. This application assumes that the trajectory is radial. Since both tangential and radial type crushers work whether the assumption is correct is not critical to the validity of the machine. To summarize the operation of the prior art rock crushers, while most of them are designed so that they have one or even two positional adjustments of the breaker blocks, none of them are designed so that adjustment of the block may be effected from outside the crusher, nor does any prior art crusher provide all three (3) of the major types of adjustment; namely, radial, vertically and rotationally.